By Caitlin Birdsall
Over the past few weeks, the BC Cetacean Sightings Network has received many reports of grey whales passing through urban waters. Reports have arrived from White Rock, Tsawwassen, Richmond, and Vancouver, where coastal citizens have spotted these animals from sailboats, neighborhoods and even public parks!
Grey whales make one of the longest migrations of any mammals, from Baja Mexico where they have their calves and breed, to the food-rich Bering Sea to feast. This round trip, which can be up to 18,000 km each year, is usually broken up by stops along the B.C. coast as they snack to sustain them on their way to the Arctic! Grey whales will often feed in eel grass beds when herring eggs are plentiful; while in the Lower Mainland they are likely targeting soft, muddy-bottomed areas like Boundary Bay, where they can scoop up large amounts of sediment and filter it through short, coarse baleen in search of small invertebrates. Because these ‘urban’ sightings don’t happen every year, each report we receive is a valuable opportunity to learn where and when grey whales drop in for a snack!
Many of the grey whales spotted around the Lower Mainland this spring won’t make the entire journey to the Bering Sea. Smaller ‘resident’ populations linger in Washington and BC waters during the summer, particularly around the western edge of Vancouver Island. Researchers believe that the whales spotted by city dwellers spend the rest of their summer in these areas.
Although plenty is known about the two ends of the migration, it is the details of the routes grey whales take between them that needs further investigation. To help understand how whales navigate our waters, a team of researchers from the Vancouver Aquarium, Fisheries and Oceans Canada, NOAA and the Centre for Whale Research visited the west coast of Vancouver Island this spring to deploy satellite tags on passing grey whales. One animal was successfully tagged, and researchers were able to track the whale’s location for 12 days before the signal was lost. In those 12 days it traveled over 1,200 km up through BC waters to southeast Alaska. The whale traveled offshore most of the way, dipping in towards the coast twice, once near the northern tip of Vancouver Island and once near Rose Spit in Haida Gwaii (Queen Charlotte Islands). The grey whale research team hopes to continue this project in future years to compare the routes grey whales use to traverse our coastline, and which areas might be important ‘refueling stations’.
Although the grey whales won’t be around the Lower Mainland for long, it is important to remember that our urban waters can mean more noise disturbance and vessel collision risk for these animals. During the BC Cetacean Sightings Network 2008 fall cetacean survey off western Vancouver Island, grey whales with obvious propeller marks were noted, evidence that these large animals are sometimes struck by vessels. If you see a grey whale while out on the water, be sure to follow the Be Whale Wise guidelines by keeping at least 100m away from the animal, slowing down to less than 7 knots within 400m, and limiting your viewing time to a maximum of 30 minutes.
You can help researchers learn more about migration and habitat use of all cetaceans by reporting any sighting of whales, dolphins, porpoises or sea turtles to the BC Cetacean Sightings Network! Click here to report online, or call 1 866 I SAW ONE.
To learn more about grey whales click here!